Hello, we were previously using a Duemilanove. We've gone to the Uno at first all appeared to go well. We are sending 3 bytes of information at 60Hz. The Duemilanove with the FTDI took this no problem. However, the Uno just goes dead at that rate. I had to back it off by about 15Hz down to 45Hz to get it to perform consistently. At about 53Hz it becomes unstable and the output becomes erratic. Is this a limitation of the new native USB controller on the Uno? I saw an earlier thread about serial library incompatibility. We are using Spi for our shield and the Serial.* family of calls for our USB comms. Will using NewSerial* solve the speed issue?

I would like to use the Arduino platform in the future to replace a simulation controller platform that is now obsolete. That clearly is a task for a more sophisticated version of the Arduino but if it uses the same USB controller and that is where the performance issues lie then that wouldn't be an option.